Priority benefit is claimed for this application based on application Ser. No. PCT/00149, filed on Oct. 3, 1980, based on Japanese Application No. 90562/79, filed June 30, 1979.
This invention relates to a numerical control device having both a magnetic bubble memory and an integrated circuit memory (hereinafter IC memory) as memories for storing machining program data, and more particularly to a numerical control device capable of high-speed numerical control processing wherein machining program data is transferred to and stored in a high-speed IC memory from a non-volatile, large-capacity magnetic bubble memory by introducing power from a power source.
A numerical control device of the stored program type executes a numerical control process in accordance with a control program and machining program data which are stored in a memory in advance. Until recently, core memories have been used to store the machining program data in such numerical control devices, but there is now a growing trend toward the use of magnetic bubble memories for this purpose. The reason is that it is possible to provide a less expensive numerical control device since the magnetic bubble memory allows a large functional packing density to be achieved and is therefore less costly than a core memory, though both types of memory are similar in that they are non-volatile and large in capacity.
While the magnetic bubble memory is advantageous in that it is inexpensive and capable of retaining its memory in the event of an interruption in power, a read/write operation is performed in page units (10 to 20 bytes), and a disadvantageously long access time of several miliseconds per page is required. Hence, when a processor accesses the magnetic bubble memory directly in an effort to execute a numerical control process, program execution time is prolonged so that it becomes impossible to realize high-speed numerical control processing.